博文

EMBO Journal：番茄驯化过程中作用于耐盐性丢失的关键基因

已有 2660 次阅读 2020-4-17 09:13 |个人分类:每日摘要|系统分类:论文交流

Loss of salt tolerance during tomato domestication conferred by variation in a Na+/K+ transporter

First author: Zhen Wang; Affiliations: CAS Center of Excellence in Molecular Plant Sciences (中科院上海植物逆境生物学研究中心): Shanghai, China

Corresponding author: Jian‐Kang Zhu

Domestication has resulted in reduced salt tolerance in tomato. To identify the genetic components causing this deficiency, we performed a genome‐wide association study (GWAS) for root Na+/K+ ratio in a population consisting of 369 tomato accessions with large natural variations. The most significant variations associated with root Na+/K+ ratio were identified within the gene SlHAK20 encoding a member of the clade IV HAK/KUP/KT transporters. We further found that SlHAK20 transports Na+ and K+ and regulates Na+ and K+ homeostasis under salt stress conditions. A variation in the coding sequence of SlHAK20 was found to be the causative variant associated with Na+/K+ ratio and confer salt tolerance in tomato. Knockout mutations in tomato SlHAK20 and the rice homologous genes resulted in hypersensitivity to salt stress. Together, our study uncovered a previously unknown molecular mechanism of salt tolerance responsible for the deficiency in salt tolerance in cultivated tomato varieties. Our findings provide critical information for molecular breeding to improve salt tolerance in tomato and other crops.

驯化导致了番茄耐盐性降低。为了鉴定这种现象的潜在遗传基础，作者基于369份番茄材料，测定了根的Na+/K+比率，并进行了全基因组关联分析。结果显示，与根Na+/K+比率最相关的变异来自于SlHAK20基因，该基因编码一个HAK/KUP/KT转运蛋白家族第IV大类的成员。作者的研究显示，SlHAK20蛋白能够在盐胁迫处理下转运Na+和K+，调控Na+和K+的内稳态。作者鉴定到了SlHAK20基因上的一个编码序列变异与根的Na+/K+比率变异相关，并且赋予了番茄的耐盐性。番茄SlHAK20基因的功能敲除突变体和水稻同源基因的敲除突变体均显示对于盐胁迫的超敏表型。综上，本文的研究揭示了一个先前未知的耐盐性分子机制，作用于栽培种番茄的耐盐缺陷。作者的研究为未来番茄与其它作物中为提升耐盐性为目标的遗传育种提供了关键信息。

Synopsis

Selection of large fruits in domesticated tomato is linked to a reduction in salt tolerance. This study links domestication‐associated variation in the Na+/K+ transporter‐coding gene SlHAK20 to reduced salt tolerance in cultivated plants.

番茄驯化过程中，对于大果实的选择往往与耐盐性的降低连锁。本文的研究发现在栽培种番茄中，耐盐性的降低是由Na+/K+转运蛋白SlHAK20编码基因区的、与驯化相关的变异所引起的。

Root Na+/K+ ratios show a strong positive correlation with fruit weight during tomato domestication.
在番茄驯化过程中，根部Na+/K+比率与果实重量呈现出极强的正相关性。

A variation in SlHAK20 is associated with Na+/K+ ratio modulation in tomato roots under salt stress conditions.
在番茄中，SlHAK20蛋白中的一个变异与盐胁迫条件下根部Na+/K+比率的改变相关。

The SlHAK20Hap1 haplotype is more effective than SlHAK20Hap2 in conferring Na+ homeostasis and salt tolerance.
SlHAK20Hap1单倍型要比SlHAK20Hap2在Na+内稳态及耐盐性方面具有更强的效应。